FIELD OF THE INVENTION
This invention relates to a pressurizing-type image forming device in which a material which acts to fix an image produced in an image exposure manner by way of pressure is applied to a carrier to form a photosensitive member, or a substance having sensitivity which acts to fix an image obtained by way of pressure is applied to a carrier body to form a photosensitive and pressure sensitive member on which the image is obtained by exposure, and the obtained image is fixed by way of pressure.
An image recording material which uses a microcapsule accommodating a photosensitive composition has been proposed, for example, in Japanese Patent Public Disclosure No. 179836/1982, which is a known system for holding a synthetic polymeric walled capsule containing a vinyl compound, a photochemical polymerization initiator and a colorant precursor on a carrier thereof. The image recording method which uses this system is a system in which some of the microcapsules are hardened in a desired shape according to the image generated by exposure, and the unhardened microcapsules are burst by pressure so as to obtain a color image from the delivered colorant precursor. This system is characterized by its capability of obtaining an image of high quality by way of a dry and simple treatment. This system is, however, remarkably inferior in photosensitivity compared to the kind of system which uses a silver halogenide.
A novel recording material which can overcome the aforesaid problem and which displays high sensitivity was proposed in Japanese Patent Publication No. 117089/1985 by the applicant of this invention, whereby an image of high quality can be attained by way of a simple dry treatment. This recording material is made from a photosensitive composition in which at least a photosensitive silver halogenide, a reducer, a polymerizable compound and a color image forming material are applied to a carrier, and at least the polymerizable compound and the color image forming material are enclosed in one microcapsule.
The image recording method which records an image with the use of this photosensitive material was proposed by the applicant of this invention in the specification of Japanese Patent Publication No. 121284/1985. This method of recording an image is as follows: first a latent image is formed by way of exposing the material to an image, then the image is developed by heating, and the polymerizable compound in the portion where the latent image is present is polymerized so as to produce a high-molecular compound for the purpose of hardening the microcapsules; then, the material is laminated with an image receiving material having an image receiving layer to which a color image forming material can be transferred by pressurization, and at least a part of the microcapsules in the portion in which no latent image is present are burst for the purpose of transferring the color image forming material to the image receiving material, whereby an image is obtained on the image receiving material. In order to form a clear image when an image obtained by heat developing after exposing the material to an image on the photosensitive member is fixed on an image receiving layer, equal pressure needs to be applied under certain conditions.
In the conventional roller pressurizing method, it is difficult to apply pressure equally in the widthwise direction, and in the case of the impact pressure method in which a small sized head hits a sheet, the time required to hit the entire surface is too long.